Thailand Rental Electricity Overcharge Index: Province-by-Province, Updated Every Quarter
Every quarter, CapSolar re-runs the same reproducible nationwide sample of Thai rental listings and measures what share of listings that advertise an electricity rate charge above the OCPB official calculation-method cap of 4.88 THB/unit — building Thailand's only quarterly series on this question.
Latest quarterly index — share of advertised rates above the 4.88 cap
251/254 listings · 95% CI: 96.6–99.6%
Baseline quarter — quarter-over-quarter change appears from the next wave onward
4.88 THB/unit = the OCPB official calculation-method cap (2568 notification) · advertised-rate listings only
The CapSolar Overcharge Index for the latest quarter (Q3/2026) stands at 98.8% — of 254 listings advertising a numeric electricity rate, 251 advertised above the OCPB official calculation-method cap of 4.88 THB/unit. The median advertised rate is 7 THB/unit = 1.43× the cap, and a typical renter using 30 units/month overpays a median of about 63.6 THB/month ≈ 763 THB/year versus the cap. The index is re-measured every quarter with the same method — see the province table and trend below.
Quarterly Trend
This table accumulates one row per quarter (each wave is an independent market-snapshot sample, not a panel of the same properties). When two quarters' confidence intervals overlap, the change is reported as not statistically significant.
| Quarter | OI — % over cap | Median (THB/unit) | × cap | Rate advertised | Median excess @30 units (THB/mo) |
|---|---|---|---|---|---|
| 2569-Q3baseline | 98.8% | 7.0 | 1.43× | 63.5% | 63.6 |
The trend sparkline appears once at least 2 quarters of data exist — next wave Oct 2026.
Province Comparison Table
Only provinces with at least 5 advertised-rate listings in the latest quarter are listed individually (11 provinces); the remaining 35 provinces are combined into one row to avoid false precision. Click a column header to sort.
| Province | n total | |||
|---|---|---|---|---|
| Bangkok | 166 | 108 | 7.0 | 100.0% |
| Chon Buri | 31 | 23 | 7.0 | 100.0% |
| Chiang Mai | 23 | 17 | 7.0 | 100.0% |
| Nonthaburi | 14 | 12 | 8.0 | 100.0% |
| Pathum Thani | 16 | 9 | 7.0 | 88.9% |
| Phuket | 15 | 9 | 7.0 | 100.0% |
| Samut Prakan | 12 | 8 | 7.5 | 87.5% |
| Nakhon Ratchasima | 10 | 7 | 8.0 | 100.0% |
| Nakhon Pathom | 13 | 6 | 7.5 | 100.0% |
| Rayong | 7 | 5 | 7.0 | 100.0% |
| Ubon Ratchathani | 7 | 5 | 8.0 | 100.0% |
| Other provinces (35, combined) | 86 | 45 | 8.0 | 97.8% |
⚠ = fewer than 10 advertised-rate listings — interpret with caution (wide confidence interval).
Is your room over the cap? Enter the per-unit rate from your bill and find out instantly — you're not alone: 98.8% of advertised rates nationwide exceed the cap.
Check Your RateBangkok vs Other Provinces
Bangkok: all 108 advertised-rate listings exceed the cap (100%).
Other provinces (45): 143 of 146 advertised-rate listings exceed the cap (97.9%) — barely different from Bangkok, making this a nationwide picture, not a capital-city one.
How the Index Is Calculated
OI = 100 × (listings advertising a rate above 4.88) ÷ (all listings advertising a numeric electricity rate) — reported with a Wilson 95% confidence interval each quarter, alongside 4 companion metrics: median rate (M), median-to-cap ratio (R), transparency rate (T), and median 30-unit monthly excess (OC).
Each quarter draws a stratified systematic sample (target 400 listings) from a major public Thai rental-listings website, with SEED = the collection date (YYYYMMDD) — public and re-verifiable. Inclusion/exclusion rules, the no-outlier-trimming policy, and all six declared limitations are identical to the baseline wave. Read the full methodology on the survey report.
The Q3/2026 baseline values are permanently locked (never restated). If any rule ever has to change, the impact on cross-quarter comparability will be declared explicitly on this page.
Limitations
A condensed version of the full report's six declared limitations — read them all on the survey page.
The index covers only listings that advertise a rate (~63.5% of the sample) — 'call to ask' listings may price differently.
Advertised rates can differ from what contracts actually charge — the index measures advertised prices, not real bills.
Small-sample provinces (⚠ rows) have wide confidence intervals — their percentages can swing next quarter without the market actually changing.
Each quarter is an independent market snapshot (not a panel) — small quarter-to-quarter moves may be sampling noise; overlapping confidence intervals are reported as not significant.
Download the Data
Open data under CC BY 4.0 — free for media and research reuse; cite 'CapSolar Overcharge Index' with a link back to this page.
About This Index
Produced by the CapSolar team, a Thai commercial solar provider that tracks Thailand's electricity tariff structure as day-to-day work. The index is a public-data project: nothing is sold to tenants, and it accepts no sponsorship from any listing platform or landlord.
FAQ
Related Reading
Full Survey Report (Jul 2026)
Full methodology, price distribution, water charges, six limitations
Rental Electricity Checker
Enter your rate — instantly see if it's over the cap
Rental Electricity Law 2026
Tenant rights under the OCPB notification + complaint channels
Electricity Price per Unit 2026
Per-unit rates by user class: home / rental / business
Thailand Electricity Tariff
MEA/PEA rates, the Ft charge, and the full bill structure
Is Your Room in the 98.8%?
Enter the per-unit rate from your contract or bill and compare it against the OCPB calculation-method cap — free, 10 seconds.
Check Your Rate